Illumination device

Abstract

An embodiment of an illumination device comprising a broad band artificial light source and a non-liquid chromatic diffuser transparent to visible light comprising a dispersion of elements of nanometrical dimensions of a first material with of certain refractive index in a second material with different refractive index, wherein the light is scattered producing a separation and different distribution between cold and hot components of the light originally produced by the source, according to a scattering process in “Rayleigh” regime. The device allows illumination effects similar to those of natural outdoor environments to be reproduced in indoor environments.

The invention claimed is: 
     
       1. An illumination device comprising:
 a broad-band artificial light source comprising one or more active elements which are configured to emit photons or to absorb photons and then re-emit photons at a higher wavelength; and 
 a chromatic diffuser; 
 wherein the maximum dimension of said chromatic diffuser is equal to or greater than twice the minimum dimension of the projection of the largest of said active elements in a plane perpendicular to the maximum emission direction of said light source, wherein the maximum dimension of said chromatic diffuser is defined as the maximum distance between any two points belonging to the projection of the chromatic diffuser in a plane perpendicular to the maximum emission direction; and wherein the chromatic diffuser is configured to produce a narrow inner cone of transmitted light and a wider outer cone of diffused light, the transmitted light being more intense and warmer than the diffused light. 
 
     
     
       2. The illumination device according to  claim 1 , wherein the broad-band artificial light source is formed by a blue or ultraviolet LED or laser diode, associated with a phosphor which is configured to emit at least in the yellow region. 
     
     
       3. The illumination device according to  claim 1 , further comprising a lens configured to collimate the transmitted light. 
     
     
       4. The illumination device according to  claim 1 , further comprising a lens configured to collimate the radiation generated by the broad-band artificial light source so as to form the inner cone, or to reduce the angle of divergence of said radiation. 
     
     
       5. The illumination device according to  claim 2 , further comprising a lens configured to collimate the radiation generated by the broad-band artificial light source so as to form the inner cone, or to reduce the angle of divergence of said radiation. 
     
     
       6. The illumination device according to  claim 1 , further comprising a plurality of light sources. 
     
     
       7. The illumination device according to  claim 1 , wherein the broad-band artificial light source is formed by a plurality of white light LEDs. 
     
     
       8. The illumination device according to  claim 1 , comprising an array of blue or ultraviolet LEDs, an array of phosphors and an array of collimating lenses, each LED being optically coupled to a corresponding phosphor, each phosphor being coupled to a corresponding lens. 
     
     
       9. The illumination device according to  claim 1 , wherein said broad-band artificial light source comprises a plurality of lenses, each lens being optically coupled to a corresponding active element, said lenses being interposed between the active elements and the chromatic diffuser. 
     
     
       10. An illumination device comprising:
 a broad-band artificial light source comprising one or more active elements which are configured to emit photons or to absorb photons and then re-emit photons at a higher wavelength; and 
 a chromatic diffuser; 
 wherein the maximum dimension of said chromatic diffuser is equal to or greater than twice the minimum dimension of the projection of the largest of said active elements in a plane perpendicular to the maximum emission direction of said light source, wherein the maximum dimension of said chromatic diffuser is defined as the maximum distance between any two points belonging to the projection of the chromatic diffuser in a plane perpendicular to the maximum emission direction; and wherein the chromatic diffuser is configured to produce, at each point of it, a corresponding narrow inner cone of transmitted light and a corresponding wider outer cone of diffused light, the transmitted light being more intense and warmer than the diffused light.